P0113 Code: Intake Air Temperature Sensor 1 Circuit High Input
Quick Answer
The intake air temperature sensor is sending a voltage signal that's higher than what the ECU expects, suggesting a cold or open circuit.
At a Glance
What this code means
The intake air temperature (IAT) sensor measures the temperature of air entering the engine. The ECU uses this data to adjust fuel injection — cold air is denser and needs a richer mixture, hot air needs a leaner one. P0113 means the sensor circuit voltage is abnormally high, which typically indicates the sensor is reading an extremely low (unrealistic) temperature, pointing to an open circuit or failed sensor.
Common causes
- Faulty intake air temperature sensor
- Open or broken wire in the IAT sensor circuit
- Corroded or loose IAT sensor connector
- Poor sensor ground connection
Symptoms you might notice
- Check engine light on
- Poor fuel economy (ECU may over-richen the mixture based on false cold reading)
- Rough running in warm weather
- Hard starting or black smoke on warm starts
- Engine may run rich
Can you still drive?
Yes. This is generally not an emergency. However, the engine may run less efficiently until the issue is resolved.
How serious is this code?
Low to moderate. The engine will continue to run, but fuel economy and performance may suffer. Not a repair to delay indefinitely.
Before you replace parts
Parts replacement is often not the first step. Before buying anything, it's worth checking these basics:
- Check for related codes — a companion code may point to the true root cause
- Inspect wiring, connectors, and grounds around the affected sensor or component
- Look for obvious physical damage: cracks, disconnected hoses, or corrosion
- Clear the code, drive the vehicle, and see if it returns — intermittent codes can come from loose connections
- Verify the part is actually faulty by testing it before replacing it
How to troubleshoot it
- Locate the IAT sensor — often integrated into the MAF sensor housing or on the intake air duct
- Inspect the sensor connector for corrosion or bent pins
- Use a multimeter to test the IAT sensor resistance and compare to temperature vs. resistance specifications
- Check for a broken wire between the sensor and ECU
- Replace the IAT sensor if resistance is out of spec (often inexpensive)
Tools that may help
These are the types of tools commonly used when diagnosing this code. Having the right tool can save time and help confirm a diagnosis before spending money on parts.
- Multimeter
- MAF sensor cleaner spray (if integrated with MAF)
Estimated repair cost range
IAT sensor replacement: $20–$100. If integrated with the MAF sensor, MAF replacement: $100–$350.
Costs vary significantly by vehicle, location, and whether you use OEM or aftermarket parts. These are general ranges for reference only.
When to call a mechanic
If you've completed the basic troubleshooting steps and the code keeps returning, or if you don't have access to the proper diagnostic tools, it's worth consulting a professional. A qualified technician can perform a full diagnosis and confirm the root cause before any parts are purchased. When in doubt, get a professional opinion — it can save you from an expensive misdiagnosis.
Real-world note
The IAT sensor is often integrated into the mass airflow sensor unit, meaning a fault in the IAT sensor circuit may appear alongside MAF-related codes. On many vehicles, replacing the MAF sensor resolves both concerns at once.
Informational purposes only. This guide is for educational reference and is not a substitute for diagnosis by a qualified technician. Repair costs, causes, and symptoms may vary by vehicle make, model, year, and condition. Always consult a licensed mechanic before performing major repairs.